This invention generally relates to display devices, and more particularly to a device providing a semi-permanent luminescent display.
Various types of display devices, including many toys, are in the form of writing pads or slates which are capable of exhibiting impressions formed thereon. These slates or writing pads have the advantageous feature that they may easily be erased to remove the impressions recorded thereon by separating a film or sheet from a paraffin coated surface which serves as a backing sheet. The film which is generally used for this purpose is a translucent sheet. Writing on the pad with application of requisite pressure causes an intimate contact between the translucent sheet and the paraffin coated backing to make the latter visible through the former. In this manner, impressions are recorded on the pad. However, this arrangement generally doesn't permit effective printing with rubber stamps or the like since the requisite pressures of the impressions are not achievable.
With the known constructions, the impressions recorded on the pad are generally dull. Further, the known pads generally had a short lifetime due to the weak nature of the translucent sheet used therewith. The translucent sheet used is generally brittle and becomes soiled and creased with extended use. One proposed way of prolonging the inclusion of a pliable protective plastic sheet over the translucent sheet. This has had a disadvantage, however in that the lines formed by the modified writing pad generally tend to be thicker due to the application of pressure indirectly to the plastic sheet and not directly to the translucent sheet.
Other forms of toys or recording devices are known which are substantially more complex in construction than the pad described above. These further known recording devices do not provide a luminescent display which uses a fluorescent sheet of material to provide a simple and inexpensive device which provides a fluorescent display at the points where impressions are formed thereon.